1. Field of the Invention
The present invention relates generally to classification of a musical piece containing plural notes, and in particular, to classification of a musical piece for indexing and retrieval during management of a database.
2. Background Information
Known research has been directed to the electronic synthesis of individual musical notes, such as the production of synthesized notes for producing electronic music. Research has also been directed to the analysis of individual notes produced by musical instruments (i.e., both electronic and acoustic). The research in these areas has been directed to the classification and/or production of single notes as monophonic sound (i.e., sound from a single instrument, produced one note at a time) or as synthetic (e.g., MIDI) music.
Known techniques for the production and/or classification of single notes have involved the development of feature extraction methods and classification tools which can be used with respect to single notes. For example, a document entitled xe2x80x9cRough Sets As A Tool For Audio Signal Classificationxe2x80x9d by Alicja Wieczorkowska of the Technical University of Gdansk, Poland, pages 367-375, is directed to automatic classification of musical instrument sounds. A document entitled xe2x80x9cComputer Identification of Musical Instruments Using Pattern Recognition With Cepstral Coefficients As Featuresxe2x80x9d, by Judith C. Brown, J. Acoust. Soc. Am 105 (3) Mar. 1999, pages 1933-1941, describes using cepstral coefficients as features in a pattern analysis.
It is also known to use wavelet coefficients and auditory modeling parameters of individual notes as features for classification. See, for example, xe2x80x9cMusical Timbre Recognition With Neural Networksxe2x80x9d by Jeong, Jae-Hoon et al, Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, pages 869-872 and xe2x80x9cAuditory Modeling and Self-Organizing Neural Networks for Timbre Classificationxe2x80x9d by Cosi, Piero et al., Journal of New Music Research, Vol. 23 (1994), pages 71-98, respectively. These latter two documents, along with a document entitled xe2x80x9cTimbre Recognition of Single Notes Using An ARTMAP Neural Networkxe2x80x9d by Fragoulis, D. K. et al, National Technical University of Athens, ICECS 1999 (IEEE International Conference on Electronics, Circuits and Systems), pages 1009-1012 and xe2x80x9cRecognition of Musical Instruments By A NonExclusive Neuro-Fuzzy Classifierxe2x80x9d by Costantini, G. et al, ECMCS ""99, EURASIP Conference, Jun. 24-26, 1999, Krakxc3x3w, 4 pages, are also directed to use of artificial neural networks in classification tools. An additional document entitled xe2x80x9cSpectral Envelope Modelingxe2x80x9d by Kristoffer Jensen, Department of Computer Science, University of Copenhagen, Denmark, describes analyzing the spectral envelope of typical musical sounds.
Known research has not been directed to the analysis of continuous music pieces which contain multiple notes and/or polyphonic music produced by multiple instruments and/or multiple notes played at a single time. In addition, known analysis tools are complex, and unsuited to real-time applications such as the indexing and retrieval of musical pieces during database management.
The present invention is directed to classifying a musical piece based on determined characteristics for each of plural notes contained within the piece. Exemplary embodiments accommodate the fact that in a continuous piece of music, the starting and ending points of a note may overlap previous notes, the next note, or notes played in parallel by one or more instruments. This is complicated by the additional fact that different instruments produce notes with dramatically different characteristics. For example, notes with a sustaining stage, such as those produced by a trumpet or flute, possess high energy in the middle of the sustaining stage, while notes without a sustaining stage, such as those produced by a piano or guitar, posses high energy in the attacking stage when the note is first produced. Exemplary embodiments address these complexities to permit the indexing and retrieval of musical pieces in real time, in a database, thus simplifying database management and enhancing the ability to search multimedia assets contained in the database.
Generally speaking, exemplary embodiments are directed to a method of classifying a musical piece constituted by a collection of sounds, comprising the steps of detecting an onset of each of plural notes contained in a portion of the musical piece using a temporal energy envelope; determining characteristics for each of the plural notes; and classifying a musical piece for storage in a database based on integration of determined characteristics for each of the plural notes.